1914 - 1922: F Class
F2
Built as a coastal submarine based on the doubled hulled V class with a few minor improvements. The main improvement being the addition of a stern torpedo tube. Only three were built out of the ten ordered.
After trials F1 was given larger hydroplanes and substantial plane guards
F1 and F3 were fitted with Vickers diesels, whilst F2 was fitted with MAN diesels built under licence by Whites. These boats saw little in the way of war service apart from some local defence work and were quickly disposed of.
Five further boats F4 to F8 were cancelled after the outbreak of war.
Primarily used for coastal defence. All three of the class survived the war and ended their service as training boats at Campbeltown.
